In modern surgery minimal invasive techniques are used in more and more applications. The development of technology within this relatively new field advances quickly, which results in great training requirements for surgeons. One way of rendering the training more effective is to use computer simulations. Known techniques of providing a credible simulation are very complicated and expensive with respect to computer utility in the form of processor and memory. Moreover, the result is not sufficient to provide a realistic simulation environment. The visual properties that the anatomy exhibits in reality are difficult and time-consuming to recreate in a simulation.
Within the field of laparoscopy a camera is used to supply picture information from the patient to the surgeon. The display screen shows the picture that the camera catches of the inside of, for example, the abdominal cavity. All the instruments and the anatomy with which the surgeon works are reproduced by way of the camera and the display screen. The surgeon uses the information on the display screen to control and operate his or her instruments and carry out the procedures which are required to perform the surgical operation. Since the minimal invasive techniques supply information to the surgeon via a display screen, the three-dimensional reality is reduced to two dimensions on the display screen. The picture therefore lacks, among other things, the information as to depth that exists in reality. The surgeon has to make up for this loss of information by studying lighting conditions, colours, etc.
By use of modern computer engineering, it is possible to provide realistic training situations in a virtual environment created by a computer program. In the computer program, a three-dimensional model of the object which the simulation concerns is provided. The user is provided with a projection thereof which should correspond to the picture information which in a real situation is caught by a camera. Thus, all visual information, such as instrument and anatomy, is drawn by the computer. However, there are still considerable differences between the picture information that the computer tries to recreate and the actual picture that a camera catches. A large part of the picture information that the surgeon uses in real life, for example light effects and anatomic structures, factors such as breathing and beat of the pulse, which are present in the real situation are difficult to recreate realistically in the computer.
Many complicated processes within the field of surgery are expensive, if not impossible, to fully simulate in a computer. This indicates that the simulation can only consist of short procedures which lack the continuity that is usually present when the process is carried out. For instance, in U.S. Pat. No. 5,791,907, Ramshaw et al disclose a system for simulation of an entire operation. This solution is founded on a database of recorded video sequences which visualise different procedures in an operation. The actual simulation then includes the user being introduced to a video sequence which shows a separate procedure. Subsequently, the user is asked a number of questions. Then a video sequence is played showing the continuation of the operation which is determined by the answers to the questions.